Drugs for Normal Cognitive Decline Possible

NEW YORK, March 4 -- There aren't likely to be many ethical or legal hurdles in the development of drugs that slow or reverse the cognitive decline of normal aging, experts say.

But extending that science to drugs that enhance normal cognitive ability raises a host of social and ethical questions.

Researchers have been debating this issue in light of emerging evidence that processes affecting "normal" memory loss are distinct from those for Alzheimer's disease and may be amenable to intervention.

The dysfunction was associated with the body's decreased ability to handle glucose, suggesting that reducing blood sugar -- through drugs or behavioral changes -- could stave off cognitive decline, Dr. Small and colleagues said.

In a recent panel discussion sponsored by the Alzheimer Research Forum, Dr. Small said an elevated blood glucose level was likely just one of many mechanisms that explain the cognitive decline that invariably occurs with age.

Nevertheless, the blood sugar link highlights a possible opportunity for the development of drugs to slow cognitive decline in otherwise healthy individuals. "I do think we should at least consider developing therapeutic interventions for age-related memory decline," Dr. Small said.

It may also be possible to design drugs that enhance cognition to previously unachieved levels. These would surely be in high demand, according to Hank Greely, a law professor at Stanford University in California and expert in the legal, ethical, and social issues surrounding health law and the biosciences.

"Although there are a lot of controversies about cognitive enhancement," he said, "this one will be uncontroversial, at least when it's being used by the people for whom it would be developed, for aging people with age-related memory impairment."

However, Greely said, "there are some issues to be concerned about," which he and colleagues detailed in December in a feature article in Nature.

Safety must be established for these drugs in otherwise healthy individuals, especially considering the potential for extensive off-label use once a medication enters the market.

In addition, he and Dr. Small noted that there is appropriate concern about the possibility that research funding could be diverted from more serious issues, particularly Alzheimer's disease.

Freedom of choice could become an issue as well. Currently, employers are allowed to establish education standards for employees. Greely wondered whether employers might also be allowed to force employees to take a drug to enhance cognition if their performance wasn't up to snuff.

More indirectly, an employer might establish a performance standard that would essentially require an aging employee to take a cognition enhancer to keep up.

Access to cognition-enhancing drugs wouldn't necessarily be equitable either, some experts said. Existing socioeconomic disparities could be exacerbated, especially if the drugs are expensive. In such a circumstance, wealthy families might strengthen their educational advantages over lower-income families.

Finally, Greely said, off-label use of the drugs could raise problems, particularly if drugs designed for improving cognition in older people also work in younger ones.

From a regulatory standpoint, there would be no legal reason to deny approval of medications that enhance cognitive function in healthy older adults, said Russell Katz, M.D., director of the FDA's division of neuropharmacological drug products.

By law, he said, a drug is defined as a product used for the diagnosis, cure, mitigation, treatment, or prevention of disease, or one that affects the structure or function of the body. Cognition enhancers would fall under the second category.

The demonstration of safety would be particularly important for such approvals, he said, and the FDA would require data from large and very long studies.

"We would expect that there would need to be very many patients exposed to the appropriate doses probably for much longer periods of time perhaps than we ordinarily require for the treatment of a bona fide abnormal condition," he said.

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